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        // typeof 检测数据类型，原始值类型，除了null检测值为object,其余的数据类型都是本身的;引用数据类型检测都是object,不会细分,检测函数的时候除外
        //引用数据类型前三位都是000,但是null特殊全是0

        // 8个种
         console.log(typeof "hello");//"string"
         console.log(typeof 10);//"number"
         console.log(typeof true);//"boolean"
         console.log(typeof undefined);//"undefined"
         console.log(typeof null);//**** "object"
         console.log(typeof Symbol());//"symbol"
         console.log(typeof 10n);//"bigint"

         console.log(typeof {});//"object"
         console.log(typeof []);//"object"
         console.log(typeof new Date());//"object"
         console.log(typeof /1[3-9]/);//"object"
         console.log(typeof function(){});//****"function"

         console.log(typeof []);//"object"

         //两个及两个以上 typeof 值都是 "string"
         console.log(typeof typeof []);
         //typeof []--"object"
         //typeof "object"----"string"
         console.log(typeof typeof typeof typeof typeof []);//"string"

         
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